Heather suffered months of beatings and sexual violence at the hands of her ex McMurray, convicted last year of attacking her and six other women.

The letters accuse Heather of telling lies on the witness stand, despite similar evidence from other women. The foul-mouthed rants also bizarrely demand Heather should be made to take a lie detector test.

Heather welcomed the move but accused prosecutors and police of ignoring her plight for too long.

She said: “The police said the content of the letters was hardly alarming and actually laughed at me when I complained.

“The point is he has been found guilty and is now tormenting me.

"There was supposed to be a harassment order but because sentence was deferred again nothing has happened. It’s a joke.”

McMurray has still not been sentenced for a 16-year campaign of abuse and violence against women – seven months after being convicted.

Judges will decide whether to grant the order when it goes before the court on April 22, when he learns how long he faces in prison.

Behind bars: HM Prison Perth

Heather, who has waived her right to anonymity, says she first received the letters almost immediately after McMurray was convicted last year.

Her parents have also been sent similar letters at home.

She said: “I got the first letter just after court and then another two – all with the same content and all calling me a liar and that even if he does 25 years he still wants a lie detector test.”

In the first letter, littered with bad language and spelling mistakes, the anonymous author wrote: “Hey ya lyer, if ye are trying to get my mate the jail aye when you know for a fact that he didn’t f***ing rape you or that aye ya lyin f*** it well he is demanding for the court to do a lie detector test now so that he can prove that you did lie to the police and court and that he didn’t rape you or that ya lyin dafty.”

Scottish Labour’s justice spokesman Hugh Henry said: “Victims deserve both justice and protection. In this case, the victim has had neither.

Ordeal: Heather says she first received letters almost immediately after he was convicted (Image: Victoria Stewart/Daily Record)

“The Cabinet Secretary for Justice must ensure prison authorities put an end to this intimidation immediately, and that the court service sorts out the harrowing delays which are upsetting for the victims.”

McMurray, from Fife, was jailed in August 2014 on 14 charges of sexual assault and rape.

The High Court in Edinburgh heard how he battered the women at locations in Fife between 1997 and 2013.

His reign of terror only ended when the women agreed to give evidence during a police investigation into his abuse.

He was also found guilty of abducting and holding them against their will.

Heather was only 17 when McMurray raped and beat her, at one point breaking her ribs with a dumbbell.

She only escaped after spending weeks piecing together a mobile phone he smashed.

McMurray now faces being handed a Lifelong Restriction Order after the judge in the case called for background reports, which would mean he would only be released when he was no longer deemed a risk.

A police spokeswoman confirmed Fife police were carrying out inquiries into “offensive communications”.

A spokesman for the Crown Office said they were unable to comment on live cases.